Save the 3 grand, trade your car in for a 2012 V6
which can be had now for 12k. You'll save money on the dual exhaust, CAI (the 11+ actually have a stock CAI) and get the 8.8 standard with 31 spline axles.
I'll do some math for you:
Trade in on your car according to KBB is anywhere between 8k-10k if in decent condition. Used 2012 v6 stangs are selling for around 11-14k depending on mileage, options and location. If you have more cash to spend or are willing to take a loan I would trade towards a 2013 as it received the last S197 face lift. The price of 11& up stangs has CRASHED recently since all the rentals are coming off fleet duty and flooding the market. If you were going to do this, now would be the time, until the glut works its way out and prices stabilize. Plus, upgrading to a 3.7 will open the door to many more mods since people are actively making new things for this engine all the time.